The United Nations has called on China to end the detention of what it has cited as “tens of thousands to upwards of a million Uighurs” in the far western Xinjiang province.

The UN Committee on the Elimination of Racial Discrimination on Thursday urged China to “halt the practice of detaining individuals who have not been lawfully charged, tried, and convicted for a criminal offense in any extra-legal detention center.”

The committee also called out China’s practice of racial and ethnic profiling and heavy-handed restrictions that disproportionately target the Uighur community.

China has not denied the existence of the detention centers. It says the centers are part of a broader counter-terrorism and does not target a specific group.